leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

clk: sunxi-ng: Use u64 for calculation of nkmp rate

Browse Source 
When parent rate is 24MHz and multiplier N >= 180, intermediate clock
rate doesn't fit in 32 bit variable anymore.

Because of that, introduce function for calculating clock rate which
uses 64 bit variable for intermediate result.

Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Signed-off-by: Jernej Skrabec <jernej.skrabec@siol.net>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>
This commit is contained in:
Jernej Skrabec 2018-02-14 21:08:56 +01:00 committed by Maxime Ripard
parent d897ef56fa
commit a5ebc3368e
No known key found for this signature in database
GPG Key ID: D2B4C094214DAF74
1 changed files with 18 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/clk/sunxi-ng/ccu_nkmp.c
View File

@ -20,6 +20,18 @@ struct _ccu_nkmp {
unsigned long p, min_p, max_p;
};
static unsigned long ccu_nkmp_calc_rate(unsigned long parent,
unsigned long n, unsigned long k,
unsigned long m, unsigned long p)
{
u64 rate = parent;
rate *= n * k;
do_div(rate, m * p);
return rate;
}
static void ccu_nkmp_find_best(unsigned long parent, unsigned long rate,
struct _ccu_nkmp *nkmp)
{
@ -33,7 +45,9 @@ static void ccu_nkmp_find_best(unsigned long parent, unsigned long rate,
for (_p = nkmp->min_p; _p <= nkmp->max_p; _p <<= 1) {
unsigned long tmp_rate;
tmp_rate = parent * _n * _k / (_m * _p);
tmp_rate = ccu_nkmp_calc_rate(parent,
_n, _k,
_m, _p);
if (tmp_rate > rate)
continue;
@ -107,7 +121,7 @@ static unsigned long ccu_nkmp_recalc_rate(struct clk_hw *hw,
p = reg >> nkmp->p.shift;
p &= (1 << nkmp->p.width) - 1;
return (parent_rate * n * k >> p) / m;
return ccu_nkmp_calc_rate(parent_rate, n, k, m, 1 << p);
}
static long ccu_nkmp_round_rate(struct clk_hw *hw, unsigned long rate,
@ -127,7 +141,8 @@ static long ccu_nkmp_round_rate(struct clk_hw *hw, unsigned long rate,
ccu_nkmp_find_best(*parent_rate, rate, &_nkmp);
return *parent_rate * _nkmp.n * _nkmp.k / (_nkmp.m * _nkmp.p);
return ccu_nkmp_calc_rate(*parent_rate, _nkmp.n, _nkmp.k,
_nkmp.m, _nkmp.p);
}
static int ccu_nkmp_set_rate(struct clk_hw *hw, unsigned long rate,